Catheter with High-Density Mapping Electrodes

ABSTRACT

High-density mapping catheters with an array of mapping electrodes are disclosed. These catheters can be used for diagnosing and treating cardiac arrhythmias, for example. The catheters are adapted to contact tissue and comprise a flexible framework including the electrode array. The array of electrodes may be formed from a plurality of columns of longitudinally-aligned and rows of laterally-aligned electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Patent Cooperation Treatyapplication no. PCT/US2018/054084 (“the '084 PCT”), filed 3 Oct. 2018,now pending, which claims the benefit of U.S. provisional applicationNo. 62/572,186 (“the '186 provisional), filed 13 Oct. 2017. The '084 PCTand '186 provisional are hereby incorporated by reference as thoughfully set forth herein.

BACKGROUND

a. Field

The instant disclosure relates to high-density electrophysiology mappingcatheter assemblies and to map-ablate catheter assemblies for diagnosingand treating cardiac arrhythmias via, for example, radiofrequencyablation. In particular, the instant disclosure relates to flexiblehigh-density mapping catheter assemblies, and to flexible ablationcatheter assemblies including onboard, high-density mapping electrodes.

b. Background Art

Intravascular catheters have been used for non-invasive cardiac medicalprocedures for many years. Catheters may be used, for example, todiagnose and treat cardiac arrhythmias, while positioned within apatient's vasculature that is otherwise inaccessible without a moreinvasive procedure.

Conventional electrophysiology mapping catheters may include, forexample, a plurality of adjacent ring electrodes encircling alongitudinal axis of the catheter and constructed from platinum or someother metal. These ring electrodes may be relatively rigid. Similarly,conventional ablation catheters may comprise a relatively rigid tipelectrode for delivering therapy (e.g., delivering RF ablation energy)and may also include a plurality of adjacent ring electrodes. In manyapplications, it can be difficult to maintain good electrical contactwith cardiac tissue when using these conventional catheters and theirrelatively rigid (or nonconforming), metallic electrodes, especiallywhen sharp gradients and undulations are present.

Whether mapping or forming lesions in a heart, the beating of the heart,especially if erratic or irregular, complicates matters, making itdifficult to keep adequate contact between electrodes and tissue for asufficient length of time. These problems are exacerbated on contouredor trabeculated surfaces. If contact between the electrodes and tissuecannot be sufficiently maintained, quality lesions or accurate mappingare unlikely to result.

The foregoing discussion is intended only to illustrate the presentfield and should not be taken as a disavowal of claim scope.

BRIEF SUMMARY

The instant disclosure relates to high-density electrophysiology mappingcatheter assemblies and to map-ablate catheter assemblies for diagnosingand treating cardiac arrhythmias via, for example, radio-frequencyablation. In particular, the instant disclosure relates to flexiblehigh-density mapping catheter assemblies, and to flexible ablationcatheter assemblies including onboard high-density mapping electrodes.

Aspects of the present disclosure are directed to basket cathetersincluding an elongated catheter shaft with proximal and distal ends, aflexible basket catheter with a plurality of splines, and a plurality ofelectrodes mounted to the splines. The flexible basket catheter iscoupled to the distal end of the catheter shaft and conforms to tissuewhen extended into a deployed configuration. The plurality of electrodesare further organized into triangular-shaped cliques along each of thesplines. In more specific embodiments, each of the splines nest withadjacent splines when the flexible basket catheter is actuated into acontracted configuration.

Some embodiments are directed to a planar array catheter including anelongated catheter shaft with proximal and distal ends. The elongatedcatheter shaft defines a catheter longitudinal axis extending betweenthe proximal and distal ends. The planar array catheter further includesa flexible, planar array coupled to the distal end of the cathetershaft. The planar array conforms to tissue, and includes two or morearms extending substantially parallel with the longitudinal axis. Eachof the arms has a plurality of electrodes mounted thereon. Theelectrodes on each arm are grouped into cliques of three or moreelectrodes defining a two-dimensional shape. In some specificembodiments, the plurality of electrodes on each arm are situated in atleast two columns oriented substantially parallel with the longitudinalaxis.

Various embodiments of the present disclosure are directed to a linearcatheter including an elongated catheter shaft with proximal and distalends, and a flexible, distal tip assembly at the distal end of thecatheter shaft. The distal tip assembly conforms to tissue, and includesa plurality of electrodes. The plurality of electrodes are grouped intocliques of three or more electrodes, with each clique sampling theelectrical characteristics of contacted tissue in at least twosubstantially transverse directions. In such embodiments, thecenter-to-center distance between the electrodes in each clique may bebetween 0.5 and 4 millimeters. In various specific embodiments, theelectrical characteristics sampled by the electrodes in the clique arecollectively indicative of the true electrical characteristics of thecontacted tissue independent of the orientation of the linear catheterrelative to the tissue.

The foregoing and other aspects, features, details, utilities, andadvantages of the present disclosure will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various example embodiments may be more completely understood inconsideration of the following detailed description in connection withthe accompanying drawings, in which:

FIG. 1A a plan view of a tip portion of a planar array catheter forhigh-density electrophysiology mapping, consistent with variousembodiments of the present disclosure.

FIG. 1B is an isometric side view of the tip portion of the planar arraycatheter of FIG. 1A depicted in a flexed configuration, consistent withvarious embodiments of the present disclosure.

FIG. 1C is a close-up, isometric view of an arm portion of the planararray catheter of FIG. 1A, consistent with various embodiments of thepresent disclosure.

FIG. 1D is a cross-sectional, side view of the planar array catheter ofFIG. 1A, consistent with various embodiments of the present disclosure.

FIG. 2A is a partial, isometric view of a high-density mapping catheter,consistent with various embodiments of the present disclosure.

FIG. 2B is a partial, isometric view of the high-density mappingcatheter shown in FIG. 2A depicted in a flexed configuration,representing contact between the catheter tip and cardiac tissue,consistent with various embodiments of the present disclosure.

FIG. 2C is a partial view of a flat pattern design of an electrodecarrier band on the high-density mapping catheter shown in FIG. 2A,consistent with various embodiments of the present disclosure.

FIG. 3A is a partial, isometric view of a tip region of an ablationcatheter having distal high-density mapping electrodes, consistent withvarious embodiments of the present disclosure.

FIG. 3B is an enlarged, partial view of the distal tip of the ablationcatheter of FIG. 3A, consistent with various embodiments of the presentdisclosure.

FIG. 4A is a plan view of a basket catheter in an expandedconfiguration, consistent with various embodiments of the presentdisclosure.

FIG. 4B is a plan view of the basket catheter of FIG. 4A in a contractedconfiguration, consistent with various embodiments of the presentdisclosure.

FIG. 4C is an enlarged, plan view of a spline section of the basketcatheter of FIG. 4A, consistent with various embodiments of the presentdisclosure.

FIG. 5A is a plan view of a basket catheter in an expandedconfiguration, consistent with various embodiments of the presentdisclosure.

FIG. 5B is a plan view of the basket catheter of FIG. 5A in a contractedconfiguration, consistent with various embodiments of the presentdisclosure.

FIG. 5C is an enlarged, plan view of a spline section of the basketcatheter of FIG. 5A, consistent with various embodiments of the presentdisclosure.

FIG. 5D is an enlarged, top view of the basket catheter of FIG. 5A,consistent with various embodiments of the present disclosure.

FIG. 6A is a plan view of a basket catheter spline, consistent withvarious embodiments of the present disclosure.

FIG. 6B is an enlarged, plan view of a portion of the basket catheterspline of FIG. 6A, consistent with various embodiments of the presentdisclosure.

FIG. 7A is a plan view of a basket catheter spline, consistent withvarious embodiments of the present disclosure.

FIG. 7B is an enlarged, plan view of a portion of the basket catheterspline of FIG. 7A, consistent with various embodiments of the presentdisclosure.

FIG. 8A is a plan view of two interleaved basket catheter splines,consistent with various embodiments of the present disclosure.

FIG. 8B is an enlarged, plan view of a portion of the two interleavedbasket catheter splines of FIG. 8A, consistent with various embodimentsof the present disclosure.

While various embodiments discussed herein are amenable to modificationsand alternative forms, aspects thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe scope of the disclosure including aspects defined in the claims. Inaddition, the term “example” as used throughout this application is onlyby way of illustration, and not limitation.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of the present disclosure are directed to flexible,high-density electrophysiology mapping catheters and map-ablatecatheters. In general, the distal portions of these various cathetersmay comprise an underlying support framework that is adapted to conformto and remain in contact with tissue (e.g., a beating heart wall).

Aspects of the present disclosure are directed toward planar arraycatheters and basket catheters for electrophysiology mapping. Morespecifically, many embodiments of the present disclosure utilize printedcircuit boards (e.g., flexible printed circuit boards) to form theplanar array arms and/or basket splines. Further, aspects of the presentdisclosure include a plurality of electrodes positioned along the planararray arms and/or basket splines. In such embodiments, the planar arrayarms and/or basket splines may have electrodes conductively coupled tothe flexible circuit boards that at least partially form arms and/orsplines. Resulting cliques (or groups) of independently addressableelectrodes facilitate electrophysiology measurements of tissue, incontact with the electrodes, which are orientation independent. That is,measurements may be taken across bi-pole pairs of electrodes within eachclique (with a known distance therebetween) to capture measurements inat least two orthogonal orientations. In more advanced three-dimensionalelectrogram analysis, electrophysiology measurements may be captured inthree orthogonal planes. In some embodiments, it may be desirable forthe electrodes of a clique to be placed equidistant one another tofacilitate enhanced electrogram fidelity.

Aspects of the present disclosure are directed toward varioushigh-density electrode array catheters with substantially uniformelectrode spacing and/or known and constant spacing between electrodes.The array of electrodes includes a plurality of bi-pole pairs thatfacilitate electrophysiology mapping of tissue in contact with theelectrodes. More advanced embodiments of the present disclosure mayutilize orientation independent sensing/omnipolar technology (“OIS/OT”)and related algorithms to mitigate the need for substantially squareelectrode arrays. OIS/OT and related algorithms are discussed in moredetail in U.S. provisional application No. 61/944,426, filed 25 Feb.2014, U.S. application Ser. No. 15/118,522, filed 25 Feb. 2015, andinternational application no. PCT/US2014/011940, filed 16 Jan. 2014, allof which are hereby incorporated by referenced as though fully disclosedherein.

Conventional mapping catheter designs employ bi-pole electrodeconfigurations to detect, measure, and display electrical signals fromthe heart. However, such conventional mapping catheter designs may beprone to error associated with the orientation of the bi-pole electrodepairs relative to an electrical wavefront of the heart, and result insensed electrical signals and electrophysiology mapping results that maybe orientation dependent; and accordingly may not actually reflect thetissue properties. To mitigate this risk, aspects of the presentdisclosure are directed to signal processing techniques which may samplea plurality of bi-pole electrode pair configurations, with varyingorientations, to produce electrophysiology mapping results which areindependent of orientation. To facilitate such signal processingtechniques, respective electrophysiology mapping catheters (e.g.,linear, planar array, and basket) may utilize cliques of electrodes withspacing that is constant over time.

Various embodiments of the present disclosure are directed toelectrophysiology mapping catheters, such as linear arrays and basketcatheters, where each spline and/or arm includes more than one column ofelectrodes extending a length of the catheter—negating the need to takemeasurements across splines/arms. This greatly improves the accuracy ofthe resulting electrical signal maps, as the relative distance ofelectrodes on the same arm/spline are not prone to changes in distanceover time as electrodes on adjacent arms/splines. Moreover, theelectrophysiology basket catheters, during a diagnostic procedure, maybe operated anywhere between an expanded and contracted state as therelative distance between electrodes within a clique on each arm/splinedoes not change during movement of the catheter arms/splines, or inresponse to tissue contact.

Further aspects of the present disclosure are directed towardeliminating a distal cap of an electrophysiology basket catheter, whichfacilitates the sampling of electrogram data from the distal most tip ofthe basket.

Details of the various embodiments of the present disclosure aredescribed below with specific reference to the figures.

FIG. 1A is a plan view of a tip portion 110 of a planar array catheter101 for high-density electrophysiology mapping, consistent with variousembodiments of the present disclosure. The tip portion 110 includes aflexible array of (micro)electrodes 102 _(1-N) distributed along a topsurface of arms 103, 104, 105, 106. The four longitudinally-extendingarms comprise the flexible framework of the planar array. In variousembodiments of the present disclosure, the arms 103, 104, 105, 106 areflexible printed circuit boards. In the present embodiment, each armincludes two columns of electrodes 102 _(1-N) extending a length of thearms. The relative spacing of the electrodes, in some embodiments, maybe between 1.5-3 millimeters (center-to-center spacing). While variousembodiments of the present disclosure are directed to spot electrodesthat are printed on flexible circuit boards, such embodiments may bereadily adapted to facilitate the use of ring electrodes on the arms103, 104, 105, 106 with the position and spacing disclosed herein. Thefour arms 103, 104, 105, 106 comprise a first outboard arm 103, a secondoutboard arm 106, a first inboard arm 104, and a second inboard arm 105.These arms may be laterally separated from each other (when deployed) byapproximately 3.3 millimeters (“mm”), for example. In some specificembodiments, the relative spacing of the electrodes 102 _(1-N) may be 1mm or less. Although the planar array depicted herein includes four arms103, 104, 105, 106, other embodiments with varying numbers of arms,relative electrode spacing, the number of total electrodes on each arm,the number of rows and columns of electrodes on each arm, and placementof electrodes on one or both sides of the planar array are readilyadaptable and envisioned by the present disclosure.

Consistent with the embodiment disclosed in FIG. 1A, some specificembodiments of the planar array catheter may include electrodes ofvarying sizes. For example, the most-distal electrode 102 on the firstoutboard arm 103 and/or the most-proximal electrode 102 on the secondoutboard arm 106 may be larger in surface area. These enlargedelectrodes may be used, for example, for precise localization of theflexible array in impedance-based navigation systems. In someembodiments, the larger electrodes may facilitate tissue ablation. Insuch an embodiment, the larger electrodes may be driven with an ablationcurrent between two or more of the larger electrodes, if desired, forbipolar ablation, or, alternatively to drive ablation current in aunipolar mode between one or both of the enlarged electrodes and, forexample, a patch electrode located on a patient (e.g., on the patient'sback). Unipolar or bipolar ablation may also be conducted between thesmaller electrodes and/or a combination of smaller and larger electrodes102. Alternatively or concurrently, current may travel between one ormore of the enlarged electrodes and any one or all of the smallerelectrodes. This unipolar or bipolar ablation may be used to createspecific lines or patterns of lesions.

As further shown in FIG. 1A, a catheter shaft 107 is coupled to a tipportion 110 (including the planar array) via a proximal bushing 108which receives the one or more arms 103, 104, 105, 106 of the planararray. A distal portion of the catheter shaft 107 may include radiopaquemarker bands 111 to facilitate fluoroscopic visualization of thecatheter within a patient's cardiovascular system. In other embodiments,the radiopaque marker bands 111 may be localization coils to facilitatevisualization of the planar array in an impedance-based, magnetic-based,or hybrid type navigation system (e.g., such as the MediGuide™ Systemsold by Abbott Laboratories). In further embodiments, the planar arraymay include a combination of radiopaque marker bands and localizationcoils.

FIG. 1B is an isometric side view of the tip portion 110 of the planararray catheter 101 of FIG. 1A for high-density electrophysiology mappingand is depicted in a flexed configuration (representing contact betweenthe catheter tip and cardiac tissue), consistent with variousembodiments of the present disclosure. In FIG. 1B, the planar, flexiblearms 103, 104, 105, 106 are flexed to conform to the cardiac tissue (notshown), enabling a physician to maintain contact between several of theelectrodes 102 _(1-N) and the tissue. This enhances the accuracy, andthe corresponding diagnostic value, of the recorded informationconcerning the heart's electrical activity.

While many embodiments of the present disclosure are directed toelectrophysiology mapping, embodiments of the present disclosure mayalso be configured for pacing (as well). For example, one or moreelectrodes 102 _(1-N) may send pacing signals to, for example, cardiactissue.

While some embodiments are directed to a planar array structuresubstantially comprising flexible printed circuits, the arms 103, 104,105, 106 may alternatively (or in addition to) include (or be reinforcedwith) a flexible or spring-like material such as nitinol. Theconstruction (including, for example, the length and/or diameter of thearms) and material composition of the arms may be tailored for specificapplications. For example, desired resiliency, flexibility, foldability,conformability, and stiffness characteristics (including one or morecharacteristics that may vary from the proximal end of a single arm tothe distal end of that arm, or between or among the plurality of armscomprising the planar array). The foldability of materials such asnitinol, or flexible circuit board materials (e.g., thin polymer films)provides the additional advantage of facilitating insertion of theplanar array into a delivery catheter or introducer, whether duringdelivery of the catheter into the body or removal of the catheter fromthe body at the end of a procedure.

The high-density electrode configuration of the variouselectrophysiology mapping catheters disclosed herein may find particularapplication for (1) defining regional propagation maps on, for example,one millimeter square areas within the atrial walls of the heart; (2)identify complex fractionated atrial electrograms for ablation; (3)identify localized, focal potentials between the electrodes for higherelectrogram resolution; and/or (4) more precisely target areas forablation. The mapping catheters and ablation catheters disclosed hereinare constructed to conform to, and remain in contact with, cardiactissue despite (potentially erratic) cardiac motion. The contactstability of the catheters disclosed herein during cardiac motionfacilitates improved mapping accuracy and ablation contiguity due tosustained tissue-electrode contact. While various embodiments of thepresent disclosure are presented in terms of endocardial applications,the catheters described herein may also be directed for use inepicardial applications.

Though not shown in FIGS. 1A-B, various embodiments of the planar arraycatheter 101 may include one or more irrigation ports. For example, aproximal irrigant port(s) may be located on/at the distal end ofproximal bushing 108, the proximal irrigant port(s) positioned todeliver irrigant to or near the point where the electrode carrying arms103, 104, 105, 106 exit from the distal end of the proximal bushing 108that is mounted on the distal end of the catheter shaft 107 in thisembodiment. In some more specific embodiments, a second, distalirrigation port(s) may be located near the distal intersection of thearms 103, 104, 105, 106 and on or near distal tip 109. In yet furtherembodiments, if desired, multiple irrigation ports could be present atvarious positions along the arms 103-106. Where more than one irrigantport is positioned at proximal and/or distal ends of the planar array110, more uniform irrigant distribution at or near the proximal/distalapex of the arms 103-106 may be facilitated.

FIG. 1C is a close-up, isometric view of a portion of arm 106 of thehigh-density mapping catheter 101 of FIG. 1A, consistent with variousembodiments of the present disclosure. The arm 106 includes two columnsof electrodes 102 _(1-N) extending along a length of the arm. Each setof three adjacent electrodes forms a clique of electrodes 112 ₁₋₃. Eachclique is capable of mapping the electrophysiology of tissue in contacttherewith in a manner that is independent of the orientation of anindividual bi-pole electrode pair within the clique used to sense theelectrical characteristics of the tissue. Specifically, the cliques arecapable of sampling the electrical signal passing through the contacttissue in at least two orientations. For example, a first bi-pole pairof electrodes in an example clique 112 ₁ samples an electrical signalpassing through the contact tissue in an x-orientation, and a secondbi-pole pair of electrodes in the clique 112 ₁ samples a secondelectrical signal passing through the contact tissue in a y-orientation.Signal processing circuitry may then be used to determine the trueelectrical signal for that location. The two bi-pole pairs, thoughsubstantially in the same location and in contact with the same tissuevolume, may sample different electrical characteristics of the tissuedue to the directionality of the electrical activation wave frontstraveling through the heart. The electrical activation wave frontstypically emanate from a sinoatrial node, and atrioventricular node;however, interfering electrical signals may also emanate from one ormore of the pulmonary veins.

Importantly, to facilitate determination of important electricalcharacteristics of the tissue (e.g., impedance), the distance betweenthe first bi-pole pair (D_(A)) and the distance between the secondbi-pole pair (D_(B)) must be known and/or constant. In FIGS. 1A-D, thespacing of electrodes 102 _(1-N) on arms 103-106 is constant.Furthermore, in various embodiments it may be desirable for the distancebetween the two sets of bi-pole pairs for a single clique 112 to be thesame (D_(A)=D_(B)).

FIG. 1D is a cross-sectional, side view of an arm 106 of the planararray catheter 101 of FIG. 1A, consistent with various embodiments ofthe present disclosure. As shown in FIG. 1D, some embodiments of theplanar array catheter 101 may include a complimentary set of electrodesto the two columns of electrodes 102 _(1-N) mounted on a top surface 198of the arm 106. The second set of electrodes 102′_(1-N) facilitates bothelectrophysiology mapping with either side of the planar array, as wellas the ability to detect electrical signal flow through the cardiacmuscle in a z-orientation. As discussed in reference to FIG. 1C, a setof electrode cliques 112 ₁₋₃ on a top surface 198 of the planar arraymay detect electrical signal flow through the cardiac tissue in x and yorientations, while another electrode 102′ on the bottom surface 199 ofthe planar array (when used in conjunction with one of the electrodes102 of the same clique on the top surface 198) facilitates determinationof electrical characteristics in the z-orientation. FIG. 1D shows anumber of cliques 112 ₄₋₆ from a cross-sectional, side view of theplanar array catheter 101. Similar to the positioning of the electrodes102 on the top surface 198, it is desirable for the distance between thebottom electrodes 102′ (D_(B)), and the depth of the circuit board(D_(C)) to be known. Furthermore, in various embodiments it is desirablefor the distance between the two sets of bi-pole pairs for a singleclique 112′ to be the same (D_(B)=D_(C)).

FIG. 2A is a partial, isometric view of a linear, high-density mappingcatheter assembly portion 210, consistent with various embodiments ofthe present disclosure. As shown in FIG. 2A, the tip portion 210includes interlocking rings or bands 212 of non-conductive material(e.g., polyether-etherketone also referred to as PEEK) forming theunderlying support framework for a plurality of electrodes 218. In thisembodiment, a circumferential or helical through-cut pattern 214 definesa plurality of dovetail surfaces 216. Each dovetail surface 216 has anelectrode 218 attached to it, thereby defining a flexible array ofelectrodes that are arranged in circumferential rings or bands about thetip portion 210 of the linear mapping catheter. The electrodes 218 arealso aligned in longitudinally-extending (e.g., parallel to a catheterlongitudinal axis 220) rows of electrodes that are able to flex or moveslightly relative to each other during use of the catheter (e.g.,contact with tissue). The non-conductive material of the bands 212individually insulates each electrode 218 from one another. Thenon-conductive substrate on which the electrodes 218 are mounted maycomprise PEEK. In some embodiments, the tip 210 may include a radiopaquetip cap 222 that facilitates fluoroscopic visualization. The tip cap maybe dome shaped, hemispherical, flat-topped, tapered, or any otherdesired general shape.

In the embodiment of the tip portion 210 shown in FIG. 2A-C, there areapproximately sixty-four discrete electrodes 218, and either separatelead wires that extend to each of the electrodes 218 from the proximalend of the catheter or one or more flexible circuit boards within thetip portion 210 that are electrically/communicatively coupled to each ofthe electrodes 218 and signal processing circuitry (located near aproximal end of the catheter). In some embodiments, the catheter may beeither 7 French or 7.5 French in diameter. The flexible tip 210 helps tofacilitate sustained electrode contact with cardiac tissue during, forexample, cardiac motion, which in turn improves the accuracy of theresulting cardiac electrical activity map. The circumferential orhelical cuts 214, which may be formed by a laser, create a plurality ofserpentine gaps that permit the tip to flex as the cardiac wall moves ina beating heart. When a plurality of circumferential through-cuts areused, a plurality of dovetailed (or ‘saw-toothed’) bands 212 are formed.

As in the previous embodiments, each of the electrodes 218 arepositioned equidistant relative to one another, or at least at known orconstant distances relative to one another.

FIG. 2B is a partial, isometric view of the high-density mappingcatheter assembly portion 210 shown in FIG. 2A, depicted in a flexedconfiguration. The flexed configuration representing contact between thecatheter tip 210 and cardiac tissue. While in contact with tissue, theresulting flex of the flexible tip 210 along the helical cuts 214between each of the dovetailed bands 212 creates minute changes in therelative positions of the electrodes 218. As the total flexure of thetip 210 is divided across a plurality of electrode bi-pole pairs, thetotal effect on the resulting cardiac electrical activity map is greatlymitigated.

The linear, high-density mapping catheter of FIGS. 2A-B may include anirrigated configuration. In the irrigated configuration, the cathetermay include irrigant ports that extend through the dovetailed bands 212and/or irrigant may be excreted through the helical cuts 214 (serpentinegaps) between interleaving pairs of the dovetailed bands 212.

FIG. 2C is a partial view of a flat pattern design of an electrodecarrier band (also referred to as a dovetailed band) 212 on thehigh-density mapping catheter shown in FIG. 2A, consistent with variousembodiments of the present disclosure.

As shown in FIG. 2C, the pattern includes a circumferential waistline orring 224 defined between a circumferentially-extending proximal edge 226and a circumferentially-extending distal edge 228. Each of these edgesis interrupted by a plurality of proximally-extending pads 230 ordistally-extending pads 232. Each pad in this embodiment has the shapeof a truncated isosceles triangle with sides S and a base B. Twoadjacent proximally-extending pads define a proximally-opening pocket234 between them. Similarly, on the opposite side of the circumferentialwaistline 224, two distally-extending pads 232 that are adjacent to eachother define a distally-opening pocket 236.

When two dovetail bands 212 are connected, each distally-extending pad232 flexibly interlocks in a proximally-opening dovetailed pocket 234(of the adjacent dovetail band 212), and each proximally-extending pad230 flexibly interlocks in a distally-opening dovetail pocket 236 (ofanother adjacent dovetail band 212). The interlocking pads 230 and 232,and pockets 234 and 236, of each band 212 define a plurality ofserpentine gaps between alternating electrode-carrier bands 212 whichfacilitate deformation of the catheter tip 210 in response to a forceexerted on the tip. In the present embodiment, each of the pads 230, 232includes an aperture 238 in which an electrode will be mounted. Eachaperture 238 may extend through the respective pad, from a pad outersurface to a pad inner surface.

In other embodiments, instead of circumferential through-cuts 214 (see,e.g., FIGS. 2A-B), which define a plurality of individualelectrode-carrier bands 212, the flexible tip may be formed by acontinuous helical cut.

While the embodiments of FIGS. 2A-C show bands 212 with longitudinallyoffset pads 230 and 232 on either side of waistline 224, otherembodiments may include a carrier band with a plurality of bowtie-shapedor hourglass-shaped structures extending across the waistline 224(instead of the offset pads 230 and 232). Each of the bowtie-shaped orhourglass-shaped structures having electrode-mounting apertures 238 onone or more sides of the waistline 224. Such embodiments are essentiallysymmetrical about the waistline 224, except where electrode-mountingapertures are placed only on one side of the bowtie-shaped orhourglass-shaped structures.

As shown in FIG. 2C, each band 212 includes two columns of electrodes,with each electrode coupled to a respective electrode-mounting aperture238. The two columns of electrodes extending along a waistline 224 ofthe band 212, with the relative placement of the electrodes in eachcolumn longitudinally offset relative to one another. The resultingformation creates a plurality of triangular cliques of electrodes 213₁₋₃ formed from three adjacent electrodes. Each clique 213 is capable ofmapping the electrophysiology of tissue in contact therewith, in amanner that is independent of the orientation of a single bi-poleelectrode pair. Specifically, the triangular cliques 213 of the presentembodiment are capable of sampling the electrical signal passing throughthe contact tissue in three directions (offset from one another byapproximately 60°). Signal processing circuitry may then be used todetermine the true electrical signal characteristics for that location,regardless of bi-pole pair sampling orientation. Importantly, tofacilitate determination of important electrical characteristics of thetissue (e.g., impedance), the distance between the first bi-pole pair(D_(E)), second bi-pole pair (D_(F)), and third bi-pole pair (D_(G))must be known and constant. In FIG. 2C, the spacing of the electrodes onthe band 212 are not only known and constant, but the spacing betweeneach of the electrodes in the clique 213 are equal. Accordingly, thedistance between each of the three sets of bi-pole pairs for the clique213 ₁ are equal (D_(E)=D_(F)=D_(G)).

The relative spacing of the electrode mounting apertures 238 in FIG. 2C(and thereby the electrodes), in some embodiments, may be between 1.5-3millimeters (center-to-center spacing). In some specific embodiments,the relative spacing of the electrode mounting apertures 238 may be 1 mmor less.

FIG. 3A is a partial, isometric view of a tip portion 310 of an ablationcatheter having distal high-density mapping electrodes and FIG. 3B is anenlarged, partial view of the distal tip of the ablation catheter ofFIG. 3A, consistent with various embodiments of the present disclosure.

As shown in FIGS. 3A-B an ablation catheter tip portion 310 is depictedwith an interlocking, dovetailed pattern 356 formed from conductivematerial to facilitate tissue ablation of contacted tissue viathermal/electrical energy transfer. Each of the dovetailed patterns 356that extend circumferentially about the tip portion 310 are separated bya serpentine cut 354. The distal end 344 of this flexible ablation tip310 includes a pair of symmetrically-placed, high-densitymicroelectrodes 346 for electrophysiology mapping. The distal endfurther includes two front-facing irrigation ports 348, and athermocouple or temperature sensor 350. The mapping electrodes 346 maybe mounted in a nonconductive insert 352 (as shown in FIG. 3B) toelectrically insulate the mapping electrodes from the remainder of theablation tip. In such a configuration, the flexible ablation tip 310 maybe approximately 4-8 millimeters long. In the embodiment of FIGS. 3A-B,the pads and pockets of the interlocking, dovetailed pattern 356 definedby the serpentine cuts 354 may be smaller than the corresponding padsand pockets depicted in, for example, FIGS. 2A-C, the individual pads ofthe tip portion 310 do not house electrodes. Though in otherembodiments, the pads and pockets of FIGS. 2A-C may be combined with thedistal end 344 of FIG. 3A—facilitating two arrays of high-densityelectrodes on a single catheter.

In some embodiments of the ablation catheter tip portion 310 of FIGS.3A-B, the irrigant ports 348 may be replaced with additional mappingelectrodes 346. The resulting square pattern of the mapping electrodes346 facilitates the use of the electrodes in bi-pole pair arrangements.With three or more mapping electrodes, forming a clique, on the distalend 344 of the tip portion 310, the resulting bi-pole pair arrangementsmay be independently addressable to facilitate determination ofelectrical characteristics in both x and y directions. To furtherfacilitate measuring electrical characteristics in a z-direction, one ormore mapping electrodes may be placed on a shaft of the ablationcatheter (at approximately the same center-to-center spacing as theother mapping electrodes in the clique). Signal processing circuitryreceiving the electrical signals from the electrodes may then be used todetermine the true electrical signal for that location, independent ofthe orientation of the bi-pole pairs. In such embodiments, the distalend 344 may still include irrigant ports.

In some embodiments where a z-direction measurement is desirable, fouror more electrodes may be used to form a “pyramid shaped” clique ofelectrodes.

Some specific embodiments, in accordance with the present disclosure,may combine the embodiments of FIGS. 2A-C, and 3A-B with a combinationof mapping electrodes on a distal end 344 circumferentially andlongitudinally extending along a tip portion 210/310 of the cathetershaft. The resulting embodiment facilitates electrophysiology mapping oftissue in contact with a distal end 344 of the catheter tip portion 310(as in FIGS. 3A-B) and/or a distal tip portion of the catheter shaft.This allows the clinician during an electrophysiology diagnosticprocedure to make contact with target tissue in various relativeorientations (e.g., perpendicular, parallel, etc.).

FIG. 4A is a plan view of a distal portion of a basket catheter 400 inan expanded configuration, consistent with various embodiments of thepresent disclosure. The basket is comprised of a plurality of splines403, 404, 405, 406 which are coupled to a catheter shaft 407 at aproximal end and to a distal cap or one another at a distal end 444.While the present embodiment presents a basket comprised of four splines403, 404, 405, 406, basket catheters with three or more splines arereadily envisioned with the design depending on an intended clinicalapplication and desired electrophysiology mapping granularity. Tofacilitate expansion/contraction of the basket, a deployment member 460extends along a longitudinal axis of the basket. The deployment memberin some embodiments may be a pull-wire, which extends proximally to acatheter handle at a proximal end of the catheter shaft 407. Actuationof the pull-wire causes expansion/contraction of the basket. In otherembodiments, the deployment member 460 may be a lumen which may beactuated by a manipulator on the catheter handle to expand/contract thebasket.

In the present embodiment, each of the splines 403, 404, 405, 406includes electrode islands 461 _(1-N) distributed along a length of eachspline. While the embodiments presented in FIGS. 4A-C depict electrodeislands 461 _(1-N) regularly distributed along the length of eachspline, other embodiments may include electrode islands 461 _(1-N)unevenly distributed along the splines. For example, in pulmonary veinelectrophysiology mapping applications, only a distal portion of thebasket may be in contact with tissue proximal the pulmonary veins.Accordingly, a distribution of electrode islands 461 _(1-N) may beweighted toward a distal end 444 of the basket to facilitate enhancedelectrophysiology mapping granularity in proximity to the pulmonaryveins.

Various embodiments of the present disclosure are directed to electrodeislands 461 _(1-N) on each of the respective splines 403, 404, 405, 406,with the electrode islands 461 _(1-N) on adjacent splines beinglongitudinally offset to facilitate interleaving when the basket isbeing delivered via an introducer sheath in a contracted configuration.

FIG. 4B is a plan view of a distal portion of the basket catheter 400 ofFIG. 4A in a contracted configuration, consistent with variousembodiments of the present disclosure. Small serpentine gaps 454 arelocated between each of the adjacent splines 403, 404, 405, 406. In thecontracted configuration of the basket catheter, a deployment member 460(as shown in FIG. 4A) may be extended distally to allow each of thesplines to be drawn in radially to a longitudinal axis of the cathetershaft 407. In various embodiments of the present disclosure, the splines403, 404, 405, 406 may have a natural set in either anexpanded/contracted state, and utilize the deployment member 460 toovercome the natural set.

As shown in FIG. 4B, electrode islands 461 _(1-N) on adjacent splines403, 404, 405, 406 are longitudinally offset to facilitate interleaving(also referred to as interlocking or nesting) the electrode islandminimizing collapsed basket catheter package size. To facilitate thecollapsed state of the splines 403, 404, 405, 406, the relative distancebetween catheter shaft 407 and distal end 444 is increased viadeployment member 460.

FIG. 4C is an enlarged, plan view of a portion of spline 405 of FIG. 4A.The enlarged, plan view further shows one of the plurality of electrodeislands 461 _(1-N) distributed along a length of the spline 405. Theelectrode islands 461 _(1-N) may include three or more electrodes 402configured in a clique 412 ₁. The cliques of electrodes may be used invarious bi-pole configurations to facilitate measurement of electricalcharacteristics of tissue in contact with the electrodes. Each clique iscapable of measuring signals indicative of the unique orientationspecific electrical characteristics of the tissue in at least two ormore orientations. For example, clique 412 ₁ in the present embodimentincludes four electrodes 402 ₁₋₄. A first bi-pole pair includeselectrodes 402 _(1,3) facilitating the collection of tissue electricalcharacteristic data in an orientation substantially parallel with thecatheter's longitudinal axis. A second bi-pole pair includes electrodes402 _(2,4) facilitating the collection of tissue electricalcharacteristic data in an orientation substantially transverse to thecatheter's longitudinal axis. To facilitate collecting this electricaldata, these bi-pole electrode pairs may be independently addressable bysignal processing circuitry. The signal processing circuitry analyzesthe received signals from the electrodes in the clique to determineorientation independent electrophysiology information of the tissue incontact with the clique electrodes.

While the present embodiment depicts each of the electrodes 402 ₁₋₄ inthe clique 412 ₁ positioned on an exterior surface of the spline 405, tofurther detect contact tissue electrical characteristics in a thirddirection, or z-direction (e.g., normal to tissue), a fifth electrode inthe clique may be mounted to an interior surface of the spline 405. Thefifth electrode may be a non-contact electrode, and may be paired withat least one of the electrodes 402 ₁₋₄ on the exterior surface of thespline 405 to determine the electrical characteristics of the tissue inthe z direction.

In various embodiments consistent with the present disclosure, thesplines and electrode islands may be formed from flexible electroniccircuit boards with each of the electrodes coupled thereto andcommunicatively coupled to signal processing circuitry via electricaltraces that extend along interior or exterior surfaces of the flexibleprinted circuit board. In some specific embodiments, each of the splinesmay consist of a nitinol strut. The flex circuit may be either bondeddirectly to the nitinol, or, alternatively, the flex circuit may bedirectly bonded to pebax tubing which houses the nitinol strutinternally.

In some specific embodiments, the electrodes may be 0.8 millimeters indiameter with a total surface area of 0.5 mm². The electrodes in eachclique may be various sizes and shapes. For example, a smaller sizeelectrode(s) (e.g., 0.8 mm in diameter) for electrophysiology mapping,and larger size electrode(s) that may be capable of bothelectrophysiology mapping and have a large enough impedance tofacilitate localization in an impedance or hybrid-based catheternavigation system (e.g., MediGuide™ System, and/or EnSite NavX system).In one particular embodiment, the smaller electrophysiology mappingcatheters may be coupled to an external-facing surface of the splinesfor direct contact with tissue, with larger, non-contact navigationelectrodes coupled to an internal-facing surface of the splines.

While it may be desirable in some embodiments to have equal spacingbetween all of the electrodes in a clique, knowledge of the relativespacing between each of the electrodes which form bi-pole pairs issufficient to accurately capture orientation-specific electricalcharacteristic data of tissue in contact with the electrodes. In somespecific embodiments, edge-to-edge spacing for one or more of thebi-pole pairs of electrodes may be between 2-2.5 millimeters. Tosimplify signal processing, consistent spacing between all of theelectrodes in a clique or across the entire basket catheter may bedesirable. In yet other specific embodiments, center-to-center spacingof the electrodes in a clique may be between 0.5-4 millimeters.

Various embodiments of the present disclosure are directed to cliques ofelectrodes forming a 2×2 array, and a triangular-shaped clique withelectrodes positioned at each corner. Any of these clique configurationsare sufficient to determine contacted tissue electrical characteristicsin two or more orientations. Some embodiments of the triangular-shapedclique may form a right-triangle or an isosceles triangle. Someembodiments of the isosceles triangle include a vertex angle between30-140°. More complex cliques may include five or more electrodes tofacilitate sampling electrical characteristics of a tissue at relativeorientations of less than 90°. Such an embodiment further reduces theelectrophysiology mapping error associated with the directionality of anelectrical wavefront traveling through the heart.

FIG. 5A is a plan view of a basket catheter 500 in an expandedconfiguration, consistent with various embodiments of the presentdisclosure. The basket is comprised of a plurality of splines 503, 504,505, 506 which are coupled to a catheter shaft 507 at a proximal end andto a distal cap or one another at a distal end 544. While the presentembodiment presents a basket comprised of four splines 503, 504, 505,506, basket catheters with three or more splines are readily envisionedwith the design depending on an intended clinical application anddesired electrophysiology mapping granularity. To facilitateexpansion/contraction of the basket, a deployment member 560 extendsalong a longitudinal axis of the basket. The deployment member in someembodiments may be a pull-wire, which extends proximally to a catheterhandle at a proximal end of the catheter shaft 507. Actuation of thepull-wire causes expansion/contraction of the basket.

In the present embodiment, each of the splines 503, 504, 505, 506includes ribs 561 _(1-N) distributed about a length of each spline. Eachof the ribs extends transverse to a direction of the mating spline. Thesplines and ribs facilitate distribution of electrodes across innerand/or outer surfaces thereof. In various embodiments, the splines andribs are formed from flexible electronic circuit boards, and/or haveflexible electronic circuit boards adhered to one or more surfaces ofthe splines and ribs. Each of the electrodes may be communicatively andmechanically coupled to the flexible circuit board via pads, withelectrical traces communicatively coupling the electrodes to signalprocessing circuitry.

While the embodiment presented in FIGS. 5A-D depicts ribs 561 _(1-N)regularly distributed along the length of each spline 503, 504, 505,506, other embodiments may include ribs 561 _(1-N) unevenly distributedalong the splines. For example, in pulmonary vein electrophysiologymapping applications, only a distal portion of the basket may be incontract with tissue proximal the pulmonary veins. Accordingly, adistribution of ribs 561 _(1-N) may be weighted toward a distal end 544of the basket to facilitate enhanced electrophysiology mappinggranularity in proximity to the pulmonary veins.

Various embodiments of the present disclosure are directed to ribs 561_(1-N) on each of the respective splines 503, 504, 505, 506, with theribs 561 _(1-N) on adjacent splines being longitudinally offset tofacilitate interleaving when the basket is being delivered via anintroducer sheath in a contracted configuration.

FIG. 5B is a plan view of the basket catheter 500 of FIG. 5A in acontracted configuration, consistent with various embodiments of thepresent disclosure. Small serpentine gaps 554 are located between eachof the adjacent splines 503-506. In the contracted configuration of thebasket catheter, a deployment member 560 (as shown in FIG. 5A) may beextended distally to allow each of the splines to be drawn in radiallytoward a longitudinal axis of the catheter shaft 507.

As shown in FIG. 5B, ribs 561 _(1-N) on adjacent splines 503-506 arelongitudinally offset to facilitate interleaving the ribs to minimizecollapsed basket catheter package size. To facilitate the collapsedstate of the splines 503-506, the relative distance between cathetershaft 507 and distal end 544 is increased via deployment member 560.

FIG. 5C is an enlarged, plan view of a portion of spline 505 of FIG. 5A,consistent with various embodiments of the present disclosure. Theenlarged, plan view further showing three of the ribs 561 ₁₋₃distributed along a length of the spline 505. The spline 505 and ribs561 ₁₋₃ may house a plurality of electrodes for electrophysiologymapping of cardiovascular tissue, for example. As shown in FIG. 5C, theplurality of electrodes 502 are configured in three overlapping cliques512 ₁₋₃. Each clique of electrodes may be used in various bi-poleconfigurations to facilitate measurement of electrical characteristicsof tissue in contact with the electrodes. Each clique is capable ofmeasuring the directionally distinct electrical characteristics of thecontacted tissue in two or more orientations. For example, clique 512 ₁in the present embodiment includes five electrodes 502 ₁₋₅. A firstbi-pole pair may include, for example electrodes 502 _(1,3) facilitatingthe collection of tissue electrical characteristic data in anorientation substantially parallel with the catheter's longitudinalaxis. A second bi-pole pair includes electrodes 502 _(2,4) facilitatingthe collection of tissue electrical characteristic data in anorientation substantially transverse to the catheter's longitudinalaxis.

In some specific embodiments, some of the electrodes 502 within a clique512 may be multi-purpose, while other electrodes are single-purpose. Forexample, electrodes 502 _(1,3) may function as both navigation andelectrophysiology mapping electrodes, electrodes 502 _(2,4) may functiononly as electrophysiology mapping electrodes, and electrode 502 ₅ mayfunction only as a navigation electrode. In various embodiments of thepresent disclosure, the cliques form a two-dimensional shape (e.g.,triangle, square, hexagon, etc.).

While the present embodiment depicts each of the electrodes 502 ₁₋₅ inthe clique 512 ₁ positioned on an exterior surface of the spline 505, tofurther detect tissue electrical characteristics in a third orientation(i.e., normal to tissue), one or more electrodes in the clique may bemounted to an interior surface of the spline 505. The fifth electrodemay be a non-contact electrode, and be paired with at least one of theelectrodes 502 ₁₋₅ on the exterior surface of the spline 505 todetermine the electrical characteristics of the contacted tissue in anormal direction relative to a surface of the tissue. Moreover, as thenavigation electrodes do not necessarily need to be in contact withtissue, the navigation-only electrodes may be placed on the interiorsurface of the spline 505.

FIG. 5D is an enlarged, top view of a distal end 544 of the basketcatheter of FIG. 5A, consistent with various embodiments of the presentdisclosure. FIG. 5D further shows the placement of electrode cliques 512₄₋₆ in proximity to the distal end 544 of the basket catheter. Thisdistal placement of electrodes may be particularly advantageous invarious applications (e.g., electrophysiology mapping of left atriumwith specific focus on the electrical signals emanating in and aroundthe pulmonary vein).

FIG. 6A is a plan view of a basket catheter spline 600 and FIG. 6B is anenlarged, plan view of a portion of the basket catheter spline 600 ofFIG. 6A, consistent with various embodiments of the present disclosure.The basket catheter spline 600 includes a plurality of electrodes 602_(1-N) which may be associated with one or more cliques 612. As shown inFIG. 6B, electrodes 602 _(1,3-4) are configured in an electrode clique612 ₁. The electrodes in the clique 612 ₁ may be independentlyaddressable by signal processing circuitry to detect electricalcharacteristics of tissue in contact with the electrodes via one or moreelectrode bi-pole pairs in the clique which allow for the detection ofelectrical signal variation associated with the directional flow ofelectrical signals through a cardiac muscle, for example. In the presentembodiment, the electrode clique forms an isosceles triangles with avertex angle of approximately 30°.

As shown in FIG. 6B, a number of the electrodes, electrodes 602 _(1,3)for example, are not positioned along a centerline of the spline 600.Instead, the electrodes 602 _(1,3) are positioned offset from thecenterline of the spline 600 on pads to form the desired triangularclique 612 ₁ arrangement. In such an embodiment, an adjacent spline mayhave its electrodes longitudinally offset to facilitate interleaving ofthe respective pads extruding from each spline when contracting thebasket catheter.

FIG. 7A is a plan view of a basket catheter spline 700 and FIG. 7B is anenlarged, plan view of a portion of the basket catheter spline 700 ofFIG. 7A, consistent with various embodiments of the present disclosure.The basket catheter spline 700 includes a plurality of electrodes 702_(1-N) which may be associated with one or more cliques 712. As shown inFIG. 7B, electrodes 702 ₁₋₃ are configured in an electrode clique 712 ₁.In the present embodiment, the electrode clique forms an isoscelestriangle with a vertex angle of approximately 110°.

As shown in FIG. 7B, each of the electrodes 702 are positioned offsetfrom the centerline of the spline 700 on pads to form the triangularclique 712 arrangement. In such an embodiment, an adjacent spline on thebasket catheter may have its electrodes longitudinally offset tofacilitate interleaving of the respective pads extruding from eachspline when contracting the basket catheter.

FIG. 8A is a plan view of two interleaved basket catheter splines 800and FIG. 8B is an enlarged, plan view of a portion of the twointerleaved basket catheter splines 800 of FIG. 8A, consistent withvarious embodiments of the present disclosure. The two splines 803 and804 include a plurality of electrodes 802 _(1-N) distributed along alength of the splines. In the present embodiment, each of the splines803 and 804 have a “saw-tooth” shape that facilitates seating adjacentsplines into complimentary features thereof when the basket catheter iscontracted. The saw-tooth shape further facilitates triangular cliques812 ₁ of electrodes 802 ₁₋₃, which in some embodiments form an isoscelestriangle with a vertex angle of approximately 110°.

In some embodiments consistent with the present disclosure, the cliquesof electrodes remain in a triangular-shape even when the basket catheteris in a collapsed configuration. In various embodiments, thetriangular-shaped cliques of electrodes are formed from immediatelyadjacent electrodes.

While various embodiments of high-density electrode catheters aredisclosed herein, the teachings of the present disclosure may be readilyapplied to various other catheter embodiments as disclosed, for example,in the following patents and patent applications which are herebyincorporated by reference: U.S. provisional application No. 61/753,429,filed 16 Jan. 2013; U.S. provisional application No. 60/939,799, filed23 May 2007; U.S. application Ser. No. 11/853,759 filed 11 Sep. 2007,now U.S. Pat. No. 8,187,267, issued 29 May 2012; U.S. provisionalapplication No. 60/947,791, filed 3 Jul. 2007; U.S. application Ser. No.12/167,736, filed 3 Jul. 2008, now U.S. Pat. No. 8,206,404, issued 26Jun. 2012; U.S. application Ser. No. 12/667,338, filed 20 Jan. 2011 (371date), published as U.S. patent application publication no. US2011/0118582 A1; U.S. application Ser. No. 12/651,074, filed 31 Dec.2009, published as U.S. patent application publication no. US2010/0152731 A1; U.S. application Ser. No. 12/436,977, filed 7 May 2009,published as U.S. patent application publication no. US 2010/0286684 A1;U.S. application Ser. No. 12/723,110, filed 12 Mar. 2010, published asU.S. patent application publication no. US 2010/0174177 A1; U.S.provisional application No. 61/355,242, filed 16 Jun. 2010; U.S.application Ser. No. 12/982,715, filed 30 Dec. 2010, published as U.S.patent application publication no. US 2011/0288392 A1; U.S. applicationSer. No. 13/159,446, filed 14 Jun. 2011, published as U.S. patentapplication publication no. US 2011/0313417 A1; internationalapplication no. PCT/US2011/040629, filed 16 Jun. 2011, published asinternational publication no. WO 2011/159861 A2; U.S. application Ser.No. 13/162,392, filed 16 Jun. 2011, published as U.S. patent applicationpublication no. US 2012/0010490 A1; U.S. application Ser. No.13/704,619, filed 16 Dec. 2012, which is a national phase ofinternational patent application no. PCT/US2011/040781, filed 16 Jun.2011, published as international publication no. WO 2011/159955 A1.

While the various embodiments presented in FIGS. 1-8 are amenable to theapplication of spot electrodes coupled to a flexible electronic circuit,where the flexible electronic circuit may also (partially) comprise thesplines, arms, and shaft of the various catheters, yet other embodimentsmay be directed to the use of ring electrodes crimped or swaged ontosplines, arms, and shafts comprising well-known materials in the art.The ring electrodes being electrically coupled to signal processingcircuitry using lead wires. The ring electrodes being positioned alongthe splines, arms, and shafts of the catheters to form cliques ofelectrodes with equal and known spacing therebetween. In yet otherembodiments, ring electrodes may be swaged or crimped onto a flexiblecircuit board comprising at least part of the splines, arms, and/orshaft of the various catheters disclosed herein.

Although several embodiments have been described above with a certaindegree of particularity, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thespirit of the present disclosure. It is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative only and not limiting. Changes indetail or structure may be made without departing from the presentteachings. The foregoing description and following claims are intendedto cover all such modifications and variations.

Various embodiments are described herein of various apparatuses,systems, and methods. Numerous specific details are set forth to providea thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments, the scope of which isdefined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” “an embodiment,” or the like, means thata particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” “in an embodiment,” or the like, inplaces throughout the specification are not necessarily all referring tothe same embodiment. Furthermore, the particular features, structures,or characteristics may be combined in any suitable manner in one or moreembodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

What is claimed is:
 1. A planar array catheter comprising: an elongatedcatheter shaft including a proximal end and a distal end, and defining acatheter longitudinal axis extending between the proximal and distalends; and a flexible, planar array at the distal end of the cathetershaft, the planar array configured to conform to tissue, and includestwo or more arms extending substantially parallel with the longitudinalaxis, each of the arms having a plurality of electrodes mounted thereon;and wherein the electrodes on each arm are grouped into cliques of threeor more electrodes defining a two-dimensional shape.
 2. The planar arraycatheter of claim 1, wherein the plurality of electrodes on each arm areconfigured in at least two columns oriented substantially parallel withthe longitudinal axis.
 3. The planar array catheter of claim 1, whereinthe cliques of electrodes are configured in a triangular-shape, eachclique having at least three electrodes, the clique of electrodesconfigured to sample electrical characteristics of contacted tissue inat least two substantially transverse directions.
 4. The planar arraycatheter of claim 1, wherein each arm of the planar array includeselectrodes on both an inner and outer surface, each of the cliquesincluding at least one electrode on an inner surface of the arm, the atleast one electrode on the inner surface of the arm configured tofacilitate sampling of electrical characteristics in a direction normalto the contacted tissue.
 5. The planar array catheter of claim 1,wherein the distance between at least two pairs of electrodes withineach clique is equal.
 6. The planar array catheter of claim 1, whereinthe distance between the electrodes in each clique is constant incontracted and deployed configurations of the planar array.